Geographic information systems provide for the archiving, retrieving, and manipulating of data that has been stored and indexed according to geographic coordinates of its elements. A geographic information system can be used for storing, manipulating, and displaying a three-dimensional model. The three-dimensional model can include images (e.g. satellite images, aerial images, or other images captured by a camera) that are texture mapped to geometry (e.g. terrain, buildings, structures, and other objects). The geometry of the three-dimensional model can be represented by a polygon mesh. The polygon mesh can include a plurality of polygons (e.g. triangles) that are interconnected by vertices and edges.
A polygon mesh representing a geographic area can have dense vertices and edges when they are constructed using three-dimensional scanning, stereo reconstruction, or geometry modeling techniques. For instance, a three-dimensional model of a cityscape can represent hundreds of square kilometers including many objects (e.g. buildings, cars, trees). As a result, the three-dimensional model of the cityscape can require a polygon mesh with a huge number of vertices and edges.
Mesh simplification can be necessary to reduce the size of a dense mesh in order to allow the mesh to be stored, processed, served, and rendered. Three-dimensional models of a cityscape and other scenes can model important and high-level structures, such as skylines, building outlines, and bridges. Typical mesh simplification techniques can result in objects modeled by the mesh losing their shape. This can negatively affect the appearance of the high-level structures, such as skylines, building outlines, bridges, etc., modeled by the three-dimensional model.